Telephone system



Jan. 23, K1940. C, E LQMAX 2,187,944v

b 4 INVENTOR. 39 CLARENCE ERNEST LOMAx wml@ am wmzz/ Jan. 23, 1940. c. E. LoMAx TELEPHONE SYSTEM Filed May 27, 1958 2 Sheets-Sheetl 2 INVENTOR.

CLARENCE ERNEST LOMAX mmm/,m7, Mm/M Amm 3mm IMNWMI ATTORNEYS.

Patented Jam. 23, 1940 .2,187,944 y ,'rELErlatoNr:y SYSTEM.

Clarence `Ernest Lomax, Oak lrark, Ill., assigner to Associated Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Applicationl May 27,1938, Serial No. 210,378 is claims.l (ci. nei- 3st 'Ihe present invention relates to telephone systems and more particularly to improvements in telephone systems of the intercommunication 'f type, ,y v 5 A system of the character mentioned i'srusually divorced from all central exchangeequipment, and is usedk for communication between the oices of a small organization. In the usual arrange# ment, a plurality of lines are providedwhich individually correspond .to the telephone stations of the system and individually extend to vall of the telephone stations. A line selectingy switch is" provided at each station for selectively associatf ing the telephone set at the stationwith any l5 one of the several lines. In the yusual arrangement. of this character, when a call iis, initiated at anystation, the signal device pro-videdat thatstation is .rendered inactive so-that it `can not be energized until the established connection is cleared out. In at least one system of the charf acter described, the arrangement isl such that the linesvare used only on-calls'incoming to` the, corresponding stations, the switching apparatus at each station being so arranged that, when the' telephone receiver orsubset at a particular stai tion is removed from its supporting hook o-r cradle, the telephone transmitter and receiver at4 the particular station are connected to the home 4, ,.5 line or the-line correspondingI to the particular station. With this latter type of system, acall' e is initiatedA at any station by iirst Voperating the line selecting switch provided at that station to` Y. a particular position corresponding. to a desired -line and. then operating special switching appa'- 3'5 ratus which functions to cause' the-operation of the signal device provided at the called station and also to connect thel transmitterand re.- ceiver `at the calling station. to the line corresponding to the position of the lineA selecting 40] switch.

It is an object of the present invention to provide an improved systemof the character dee" scribed which isof simple and economical .ar-'1' z rangement .and is so arranged that ca'llsfmaybe 4Q initiated at the telephone stations in 4"a vsimplied manner. y I' iv f' It is another object of the invention Atopro'l vide a system' of the character described whereiny ,T a line selecting switch is provided at each` station for selecting stations tobe called and where-iA in a single additional switchis pro-vided at each, station, which additional switchl is'.operable to.

` answer incoming calls and is. operable to per-l 515 vform all switching functions incident tothe' estaby lishing of connectionsto stations selected bythe associated line selecting switch. Y

It is a' further object of the .invention to prol vide a system of the character` described wherein `the additionalswitch provided at-each stationis operable to perform certain of its switching functions in response to the removal of. the associated receiver from its supporting hookporv cradle;l n It is still another object: of.r the invention l.to 1:-:1 10

providev :a system of'the` character described wherein talking battery orcurrentifor energizing the transmitters used at the two ends of an `established connectioniis connect-,edito the line' involved in the connection in Yan improvedmanller. l

:a is a stili further object of the invntiont' provide a system ofc'A a character described -whichis arranged in an improved manner such that the `signal device .at eachstation yis'not rendered inactive when a callv is initiatedl atthel corresponding station. Y. The invention is illustrated asbeing incorporated in an intercommunicatingl system compris-` ing a iirst station including la transmitter fand receiver and arrangedA to be interconnected with a plurality of additional stations byxlinesindividuallyextending to allof the stations and individually corresponding to the stations.' liach` of `the lines is `adapted to be usedonly on calls incoming to the correspondingy station.. There is provided at the first station a line selecting switchwhich isl operable toa plurality of posi,-l

tions" individually corresponding tol the-'station lines to select Ithe lines for use' on vcall-s. togthe. stations 'corresponding thereto.` In accordance withone'feature of the present invention, a second switch. having a plurality of operatingA positions, is provided at the'rst. station, Itogether with-means responsive tothey operation of the secondswitchto one of its operating positions yfor connecting` the transmitter .and receiver at the first station to be used in communicating' over the line correspondingA to the iirst' station irre spective of the position o-f the'line selectingv switchat thetime the secondswitch is operated,v

and means operative'in response. to operation of the second switch to another of its operating poxsitions for connecting the transmitter and re- -`cyeiver to be used in communicating; over the.' line corresponding to the position occupied by the line selecting switch. In the illustrated ernbodi- 4 ment of the invention, the second. switch is arranged to' be operated to its one position inf-response to removal vof the telephone receiver prof- ,i vided'fat the rs't station from its supporting hook or cradle. This second switchisv preferably of the form disclosed and claimed in the copending application, Serial No. 210,348, Herbert F. Obergfell, filed May 27, 1938. The normal position of the second switch is the position assumed thereby when the receiver provided at the rst stationy is replaced upon its supporting hook or cradle, means being provided, operative in response to operation ofthis switchV to its normal position, for" disconnecting'the transmitter and receiver at the rst station from all of the lines. A signal device is provided at each of the telephone stations embodied in the system and, in

accordance with a further feature of the invention, means, responsive to operation of the abovementioned second switch, are provided for causing the operation of the signal device located at the station corresponding to the position occupied by the line selecting switch of the rst station. The arrangement is such that Athe signal device provided at the rst station is only rendered inactive when the second'switch mentioned above is operated; to its one *positiony to' answer a;V call incoming to the firststation.' By this arrangement, it is possibleto signal the station even though the station is involved in an established connection, when the established connection results from a call initiated at the first station. In accordance with a` further `feature ofthe inventicn, means are also; provided, operative in response tooperation of they secondV switch to its one or answering position, for connecting a current supply source to the line corresponding to the rst station for the purpose of energizing the transmitters Aused in an established connection` including-this line.

Further features of the invention pertain to the particular arrangement of the circuit elements vwhereby the above and additional operating features are attained. i c The vnovel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to itsorganization and method of operation, together 'with 'further 'objects and advantages thereof, will best be understood by `reference to the drawings whereinFigure v`l is a crosssectional View of a fragment'of'a subsethaving embodiedctherein a switch constructed andarranged in accordance with the invention disclosed and claimed in the above-referred'to copending application, Figs.` 2, 3 and 4' illustrate diierent operating positions of the switch shown in Fig. 1;y Figs. la, 2a, 3a and 4a illustrate the arrangement of the switch contacts when the Switch occupies the lpositions respectively sho-wn in Figs. 1, 2, 3 and 4; Fig. 4b isla bottom view illustrating the contact controllingjmechanism of the switch when the switch` occupies the position shown in Fig. 4; and Fig. 5 illustrates the circuit arrangement of a circuit connected and arranged in accordance tion. 4

Referring now more particularly to Figs. 1 to with the present inven- 4b ofthe drawings, the improved switch referred` to above is illustrated as being mounted within a pedestalor base I ll of a telephone subset of the hand set type. with upstanding'lugs or arms, two of .which are indicated at ILwhich are displaced in the usual manner to provide a cradle for supporting therein the handle'portion of the hand set diagrammatically indicated at I2. The contacts and controlling mechanism thereforv are carried by av bracket member I3 which is Secured to the top pedestal Iii, and is -operating positions illustrated,

,upward "directionQ The plunger inclusive. "The springs 25 to 2s,

The pedestal i6 is provided l portion lll of the pedestal Ill by a mounting arrangement comprising spacing members !5 and screws i6. More particularly, each of the screws I extends. through openings provided in the bracket I3, the associated one of the annular spacing members I5 and the top portion" of the threaded into a tapped cap il which forms a rest for the handle of the hand The switch comprises an operatingmember in the form of a plunger i8 having a plurality of respectively, in Figs. lrto fl, inclusive, of the drawings, and a Contactvl controlling member comprising an elementvlli pivctally mounted at 29 upon two lugs 2,! projecting downward from the bracket member The' plunger i8 is mounted upon the upper portion ifi of the pedestal I .More particularly, the plunger I t is supported within a reduced c I crossv section extending through Vand snuglyengaging an opening provided inthe top portion I {l'of the pedestal lll. A nut 8, threaded onto thereduced endportion of the memberI 9, serves rigidly to secure this membercto the -portion Idiot"4 the ypedestal Il). The plunger I8 is provided with'a lcwer'portionY i511 of reduced cross section'whicl'i extends through an opening provided in thev lower 4wallof the member 9. An enlarged cap "lub having a shank threaded into the lower Yend of the plunger lVSjis yprovided for restricting the movement of the plunger in an `is normally biased in an upward direction toward one of its operating positions by a helical springu'i surrounding the portionla of the plungerrand having one'end abutting the enlarged portion of the plunger and vthe other end abutting the lowerk Wall of the member 9.

' -The contact controlling element .I9 includes an arm 22 biased to engage'the rounded Vlower surface ofthe cap lband carries two Contact actuating rollers 2321v and- 235 rotatably'niounted, re-

spectively, upon pins ri243 and Mb rigidly supported upon the elementy I 8. These rollers, which cooperatevvithv twoI fdiierent operating springs of a springv pile comprising the springs 25 to inclusive, are. mounted upon oneleg 34, of a lUA-sha-ped supporting lbracket 35i rigidly secured to the bracket member I3. springsofthis group are insulated fromeach other'by'spacing members 35 formed of insulating material, and are secured i to the leg'34v of the bracket piece 35 by screws 3l` extending' through a vface plate 38Aand the alternately spaced insulating members 35 and springs, and threaded into thev leg 3d'. A similar arrangement is used'forI mounting the springs 29 t'oy 33, inclusive, upon the other leg 3S of the U-shaped bracket piece 35. The springs of the last-mentioned group are insulatedfrom each otherv by members 40 formed of insulating mate'- rial and are secured `tol the bracket leg y39' by screws 4l extending through a face plate l2 and the alternately spaced springs and insulating members, and threaded into appropriately spaced tapped openings provided ,in the leg 39. The springs 2l, 30 and 32 of the springpile comprise the main operating springs and are movable in response to movement-of the rollers 23a and 23b carried by the contact controlling member I9. To this end, the springs 2'! and 3D are formed of relatively heavy resilient stock and are 21a and 30P- which'respectivelycooperatewith the rollers 23a and 23h. The Iresilient spring 32 is arranged to respond to movement of the spring 30 through the provision of an element 43 formed of insulating material and rigidly'secured to the spring 32. The element 43 is biased by the spring` an element 44 pivotally mounted at 45 upon a bracket piece 45 secured b-y means of a screw 4l to the bracket member I3.` The element 44 is provided with a recess 48 which is adapted to en gage the end of the arm 22 to restrain the contact controlling member` I9 in the position shown in Fig. 4. The element 44 is normally biasedto move in a counterclockwise direction toward the end of the arm 22 by a spring 49 connected between the lower end of the element 44 and the left end of the arm 22. This spring also serves to bias the right end of the arm 22 into engagement with the lower rounded surface of the cap I3b secured to the plunger I8. Movement of the element 44 ina counterclockwise direction is limited by a stop comprising an arm 5D forming a part of `the bracket piece 46 and provided at its lower end with a bent-over projection lying in the path ofl movement of the element '44.

For the purpose of releasing the locking means just described to permit' thearm 22 to .be moved under the iniiuence of thesprin'g 49 back kinto engagement with the cap IlJ carried by the g r1ght end of the arm 22 under the influence of the plunger I8, there is pivotally mounted atl52 on the element 44 a finger 53 which isv normallyv biased vinto engagement with a"be'ntover portion 54 of the element 44 by means of a lighthelical spring 55 having one end .secured tozthe bracket piece 46 andthe other end s ecured'torthev right end of the iinger 53. As best shown in Fig. 4b, the free end of the arm 22-i`s Vcut away at 22e to permit the arm to be moved between its two extreme positions without engaging the n'ger53.

With the operating member or plungerl I8` occupying its normal position as shown in Fig'. l oi?x the drawings or, more particularly,-with thehandSet I I2 resting upon its supporting pedestal II] so that the plunger I8 is depressed to its first intermediate or normal position, the contact controlling element I9 occupies a position such that the Contact springs of the spring pile have the 'arrangement illustrated in 'Fig'. la. It will be observed that, with the contact controlling memberl in'this position, only the springs 32 and 33 are in engagement. When the hand set is removed from its supporting pedestal I0, the spring 'Liorces the*l plunger I8 upward to its rst position so that the elements of the contact controlling mechanism assume the positions illustrated in Fig.,2.. More particularly, when the plunger I8 is moved upward, `the arm 22 is rotated in a counterclockwise direction under the iniiuence of the spring IISand the' rollers 23a and 23h are moved tothe right over the curved portions 2la and 3ile`respectively,'-

of the springs 2'! and 3l). so that a new arrangement of the contact springs is achieved; It will be observed vthat the cut away portion',` '22a yof the arm 2,2 passes by the nger 53 during movement of the arm 22 to the position shown in 2.. During the indicated movementfof the contact 'controlling member i9 the springs 3 2 and 33 are moved out of engagement, the spring v32 is moved '15 into engagement with the spring- 3 l', the spring 38 is moved into Vengagement withthe spring 29, and the spring 2'I is moved into engagement with the springZB. 1 v

' Ifjwith the `elementsof the switch occupying f` the spring 49 and the rollers 23@ and 23b,.by ridi ing over the inwardly curved ends 21and 30a, respectively `of the springsZ'I and 30,'force the springs 2l' and lloutward 'so that, at the end of the movement, the lcontact arrangement illustrated in Fig. `3oz is achieved. More specifically, the springs 21, 30'and 32 are moved out of engagement with the springs 28, 29 and 3|, respectively,

. and are moved into engagement with thesprings 26,34 and 33, respectively. Also, with theplunger I8l occupying its iinal operating position,v the spring 23 is forced outwardly into engagement i with thefspring 25. As the plunger I'8 is moved downward from its rst operatingv position to its nalposition the cap ID engages the rounded cam surface provided on the left end ofthe finger L53, which finger is biased into engagement with the stop 54. Due tothe engagerrijentV of the cap `I8b and the nger 53, the locking element 44 vis pivoted in a counterclockwise direction to move the elementk 44 isk snapped into engagement with the spring 49 and continuestoengage the arm 22 until the final position of the plunger I3A isreached.

If, after the plunger I8 has been depressed to its lowermostor final operating position', it is released, it starts to move upward under the inluence of the spring 'I, andthe contact controlling member I9, due` to the force 'exerted thereon by` thebiasing spring 49, follows the movement of the plunger during. aportion of its movement tol-.d ward. its first operating position.- At this time,

the lower portion' of'thelocking element'` 44 is biasedinto engagement with the right end of the arm 22 so that, when'thejplunger is 4returned to l itsnext to last operating position, vtheright end of the'arm 22'engages or drops into ythel'ecess 48 provided in the locking element` 44 `to hold the contact controlling member in 'a position, shown Fig; 4, corresponding to the next to iinal positionnf the plunger I8v while the plunger returns to itsrst operating position. During thejreturn movement of the plunger I8 the upper side of the cap Ib engages the iinger 53 to cause'thisinger to be pivoted vin a clockwise ldirection against the bias of the spring 55out of the path ofmoveme'nt 53, the iinger is rotated back' into engagement iinger out of the path of movementof the cap- |81# When the capl I8b is movedfbeyond the finger, the

with the projection 54 by thespring 55. With the i contact controlling element I9 occupying the 'posi- .tion'sho-wn in Fig. 4, the contact springsze and are disengaged, but otherwise the contact lar- Y rangement is the same asshown in Fig. 3a. l

Release of the locking meansfto permit the contact controlling member to return to'itsnormal position is effected when the hand set I2 is again placed upon .its supporting pedestal I0. Thus', when the hand set lZ'is replaced upon the supporting pedestal le; the plunger I8 yis forced downward to4 its normal or iirst rintermediate f position by the weight ofthe hand' set. During 6o of thejcap. After the cap passes over the--iingerl l elo the final movement ofthe plunger, the cap... IBD carried thereby engages the rounded end of the nger 53. Since this linger is now biased by the spring 55 into engagement with the projection or stopl 54, theV downward movement of the plunger i8 causesthe locking element 44 to be pivoted in a counterclockwise directiona sufficient amount to disengage `the right end of the arm 22 from the recess 48. Hence, the arm 22 is permitted to return to its normal position or into engagement with the cap-I8b under the influence of the spring L39 whereby the contact springs are caused toagain assume the positions shown in Fig. la.

Referring now more particularly -to Fig.A 5 of the drawings, there are illustrated two telephone stations A and. B- of an intercommunicating telephone system connected and arranged in accordance with the present invention, which stations respectively include telephone subsets of the form shown in Fig. l. The two stations A and B and the other stations of the system, not shown, include the same apparatus connected and arranged in the same manner. For this same reason, corresponding reference numerals, carrying the exponents a and b, respectively, are used to indicate corresponding elements provided atl the two stations A and B. The several stations ofv the system.- are interconnected by a plurality of lines including the lines Sil, 6I and 62, individually corresponding to the stations and each extending to all of thestations. ticularly, the line Eil corresponds to the station A, the line Si corresponds to the station B, and l the line 62 corresponds to a third station, not

shown. Considering the station A by way of example, the apparatus provided at this station comprises a transmitter` 63a, a receiver 6ta, a lineselecting switch 65e, and a signal device in the form of a bell 65a. is of the well-known rotary type and. may beof any standard commercial construction. Briefly described, the switch $5a comprises two` sets of` contacts 61a and 68a, wipers (59ai and 10a, respecl tively associated with the contact sets Bla and 68a,

and a rotatable operating element indicated by.

the dotted line laior operating the two wipers in unison. Corresponding contacts of the `two setsv 67a and 55a are respectively connected to opposite sides of the lines extending between the telephone stations of the system. Thus, the negative line conductor Gila o1" the line 60 is connected to the first contact of the set 68a and the opposite line conductor Stb. of the line 69 is connected to the rst contact of the set 61a.

are connected tothe contacts of the twovsets 61e and 68a.

There is also provided at the stationA Aa second yswitch 712% which is of the construction and arrangement shown in Figs. l to 4b, inclusive. This switch includes a plurality of contact springs 2lia to 34@ connected and arranged in an improved manner such that all of the operations incident to the answering of an incoming call and to the completion of a talking connection on a call initiated at the station A may be performed by operation of the switch. For the purpose of energizing the transmitters utilized in an established connection extending by way of one ofthe lines between two stations, there is provided a current source comprising a battery 'i3 .which is arranged to have its opposite terminals' connected to the line conductors of the line utilized. in an established connec- More par- The line selecting switch al In a similarinanner, the line conductors of the other lines.

tion through the respective windings of an impedance element 14a. The elementv 14a is provided for blocking voice frequency currents to prevent such currents from flowing through the battery 13. The arrangement is such that talking battery is impressed on a line utilized-in an established connection through the springs of the switch 'l2a provided at a called stationwhen the call resulting in the connection is answered at the called station. The battery i34 is commonly used for this purpose through the provision of a battery feed line comprising the two conductors 75 and 16. For the purpose of energizing the signal devices located at the respective stations, there is provided a second battery ll commonly associated with all of the stations and arranged to supply energizing current to the signal device at any called station overl a line comprising the conductor 'l5 and a third conductor 18.

Referring now to the operation of the system shown in Fig. 5, if v it be assumed that a` party at the station A desires to establisha connection to the station B, the line selecting switch 65a is first operated to the position corresponding to the line 3 l. This is accomplished by operating the switch 65a toa position such that the wipers S9@ and 'IIIEL engage their respective associated Second contacts. Following this operation, the hand set comprising the transmitter- 63a. and the receiver` 64a is removed from itsy supporting cradle and the operatingmemberor plunger of the switch 72a is manually depressed to its lowermost or final position. In response to the operationV ofA v the. operating plunger of the switch 'i2EL toits final position, a circuit is completed forenergizing the signal device 66'? provided at the rcalled station B. lThis circuity may be traced as extending from one terminal of thebattery 'l1 by way of the line conductor 15,'the windingof the signal device 68?, the resting contacts 33b and 32h of theswitch. 12b,` the line conductor SIb, the second contact of the set 61e, the wiper 69a, the contacts 262 and 25a' and the conductor 'I8 tothe other terminal of the battery 1l'. By repeatedly operating the plunger of the switch 'l2a to its lowermost or final position the signal device ttl? may be .energized to'l signal the called station as many times as desired.

When the plunger of the switch l2a is released after being depressed one or more times to its final position, the lockingv means described previously operates to hold the co-ntactcontrolling element of the switch in its next to final positionso that .the spring 27a engages the spring 26a, the

spring 36a engages the spring 34e, and thespring. During movementof receiver 64a provided at the substation A are.

connected to be used in communicating over the line 6l corresponding to the called station Band to the position occupied by the line selecting switch 65a. More particularly, one terminal of the subset is connected by way of the springs-ila and 34e, the wiper 'llla and the second Contact of the set 6&32L tothe negative line conductor (ila of the line (il and the other terminal of the subset is connected byway of the contact springs 1iL yand 26a, the wiper G9a and the second contact of` the set (i'liL to the opposite line -conductorxlb of the line 6l. It will be observedthat, with thel switch l2a occupying its last intermediate position, the springs 3la and 32iareout of` engage'- ment so that the battery 13 is not `connected to the conductors of the line 6I through the switch ing cradle to permit the plunger of the switch 12b to be moved from its normal `position to its rst operating position. The switch '12b responds to this movement of its operating member by. moving the spring 32h from engagement with the i spring 33D to open a further point in the abovetraced circuit for energizing the signal device Sb. Also, the spring 32h is moved intoengagernent with the spring Sib tor connectthef battery 13 to the line El through the windingsjof the lirnpedance element rTill). Thus, the lower terminal-of the battery 13 is connectedbyiway of the Aconductor 'I6' and the lower winding of the element 'Mb to the line conductor 61a of the line 6|-, and the upper terminal of the battery '13 is connected by way of the conductor 15,'the upper windingof the element 'MP and the springs 3th and 32b to the opposite line conductor Blb.V The springs 30h and Z'Ib'are respectively operated into engagement with the springsZBb and 281 in response to the operation'ocf the switch 'l2b'resulting from re` moval of the hand set from its supporting cradle, At the last-enumerated springs, the twoterminals of the subset comprising the transmitter 63h and thel receiver 64b are connected, respectively, to the line conductors Ela4 and Sib of the line 6I.

Itvwill be noted that the circuit over which the l subset is connected to the line 6I is independent of the position ofthe line selecting switch' 659, the arrangement being such that the subset is a1- ways connected to the line corresponding to the station B whenlthe hand set' is removed fromits supporting cradle. Following the operation of` the switch 12b in the` manner just described, the desired conversational circuit is fully completed.

It will bencted that, when the above-described call to the substation B is answered at this station, the operating circuit for the signal device 66h is opened at the springs 32b and 33h of the switch 12b and is held open for` the duration of the call. On the other hand, the switch 12a provided at the calling station A is operated to its last intermediate position so that the operating circuit for thejsignal device 662 provided at this station is prepared at the closed springs 32a and 33a. Thus, ,theI station A may be signaled even though the apparatusprovided atthis station yis being used to communicate over an established connection. More particularly, to'f'energize the signal device 66a, itv is only necessary to-connect the conductor 'I3 tothe conductor 601 of the line 6i! corresponding tothe station A. Such a circuit may be completed to cause the energization of the signal device lso long as the springsr32L and 33a are in engagement. Hence, it will be seen that the station A may be signaled on an incoming call even though the apparatus embodied therein is being used on a call tov another station. With the switch 'l2a arrangedin the manner described, it is possible for the calling party at the station A selectively to connect the transmitterSEL and the receiver lillEL to be used in communicating over the line 6| extending to the called substation B or to be used in communicating over the linevll corresponding to thestation A and utilized bythe party who initiates the second call., Thus, if it be assumed that theA calling party at'thepstation A `is conversing-over the Iline e 6l with the `called partyvatl the station B and the signaldevice tte operates to ,indicatel that a vcall intended for the station Ahas been yinitiatedat another station, the conversing party at the station A.. `may, by momentarily depressing 1 the plunger of the switch 72a toits normal position to release the locking means described above,`

cause-the subset ycomprising thetransmitter :63er andl the transrnitterjlifia to be disconnected from the line Si and connected to'the line 6l).k More particularly,if the `locking means of the switch 722- is released'and vthe plunger of the switchis permitted to return to its rst'operating position,

the spring 2lil is moved from engagement with tively, the transmitter 63aand the receiver 64a are connectedto the line 6U.

, After acknowledging-the second call, theparty at the station A mayv desire to continue his conversation with the party at the station B.- To this end, the line selecting switch lilla` is left,V in

25 when the springs 27a and 3l)EL are moved into l,engagementwith thefsprin'gs 29a and 28a, respec-` the position corresponding to the station B- and the plunger of the switch 'l2a again operated to its lowermost or final position .and then released, so that' the locking means oi theiswitch "I2=1L again restrains the contact controlling member of the switch inits gnal yintermediate position such that the springs 21a, 3]EL and 32a are again held in. engagement with their respective.y associ'atedsprings 28a, 34a' and SSaV'With the enui merated operatingtsprings 21a, 3|)a andi32EL in this last-mentioned position,the transmitter (i3.av

f1 andthe receiver Ella, are again connected. to be used in communicating over the line vfil corresponding to the station B'. Obviously, by repeated operations of the plunger embodied inthe switch 12a, the transmitter' 63a andreceiver'` 64@ may be transferred from onelineto the other I'o release the established Connectionextending between the stations A and B, it is only necessary i that the hand sets 'respectively providedatthese stations be replaced upon their respective supporting cradles.. When this isl done, the springs :so4 g of the two switches l2'EL and 12b are restored to the positions illustrated in Fig. 5 and correspondingnto the respective normal positions of thek y elov switches. It will be observed that, withy the switch 72a in its normal position, the spring 232e` is in engagement with .the spring SBaand -all of the other springs are disengaged Hence, 'theV circuit for energizingthe signal device -is prepared and the subset comprising-thetransmitter- 83arand 64a is 'disconnected from all f o t the lines extending between the'several stations. Similarly,i when .theswitch 12b .is restored to normal, the --circut'for' energizing the signal rdevice b is prepared at the springs 32h and 33t and the subset comprising the 'receiver 64b and i the transmitter v63kl is disconnected from tall 'of vthe linesextendingto the contacts of the switch 65u;

' .while therehasbeencscribei what is at presentconsidered to be the preferred embodiment of the invention, .it'will be understood that various modications may be made therein, and itV is intended in the appended claims to cover all such -modifications as fall'within the true spirit and scope of the invention.

What isclaimed is:

l1. In a telephone system, a -rst telephone station including a transmitter and a receiver, a plurality of additional telephone stations, a plurality of lines individually corresponding to said stations and each extending between all of said stations, each"of said lines being adapted to be used only on callsincoming to the corresponding station, said rst station including a line selecting switch operable toa plurality of positions individually corresponding to said lines to select said lines for use on calls to the stations corresponding to said lines, a second switch provided at said rst station and having a plurality of operating positions including a normal position, means responsive to operation of said second switch to one of its operating positions for connecting said transmitter and'receiver-for use-,in communicating over the Vline correspcnding'to said first station irrespective of the position of said line selecting switch at thetime said second switch is operated, means responsive to operation of said second switch to anotherof its operating positions for connecting saidy transmitter and receiver for'use inv communicating over the line corresponding `to the position of said lineselecting switch, andmeans responsive to operation of said second switch to its normal position for y disconnecting said transmitter and receiver from all of said lines.

2. In a telephone system, a rst telephone station including a transmitter and a receiver, a plurality of additional telephone stations, a signal device at each of said additional telephone stations, a plurality of lines individually corre- -sponding to said stations and each extending between all of said stations, each of said lines being adapted to be used v'only on calls incoming to the corresponding station, said first station including a line selecting switchoperable to a plurality of positions individually corresponding to said lines to select said lines for use on calls to the stations corresponding Vto said linesa second switch provided at said first station and having a plurality of operating positions,.means responsive to operation of said second switch to one of its operating positions for connecting said transmitter and receiver for use in communi eating over the line corresponding to said first station irrespective of the position of said line selecting switch at they time said second switch is operated, means responsive to operation of said second switch to a second of its operating positions for causing the operation of the signal device at the station corresponding to the posi tion of said line selecting switch, and means responsive to operation of said second switch to a third of its operating positions for connecting saidtransmitter vand receiver for use in communicating over the line corresponding to said last-mentioned station.

3. In a telephone system, a rst telephone station including a transmitter and a receiver, a

plurality of additional telephone stations, a signal device at each of said additional telephone stations, a plurality of lines individually corresponding to said stations and each extending between all of said stations, each of said lines being adapted to be used only on calls incoming to the corresponding station, said rst station in cluding a line selecting switch operable to a plurality o'fpositions individually corresponding to said lines ltoselect said lines for use on calls to thestations corresponding to said lines, a second switch provided at said rst station and having a plurality of operating positions, means responsive to operationfof said second switch to one of its operating positions for connecting said transthe station corresponding to the position of said f line selecting switch, means responsive to operation of said second switch to a third of its operating positionsfor connecting said transmitter and receiver for use in communicating over the linecorresponding to said last-mentioned station, andmeans responsive to operation of said second switch to a fourth of its operating positions for disconnecting saidtransmitter and receiver from all of said lines.

4. In atelephone system, a first telephone station, a plurality of additional telephone stations, a signal device at each of said additional stations, each of said stations including a transmitter and a receiver, a plurality of lines individually corresponding to' said stations and each extending between all ofV said stations, each of said lines beingV adapted to be used only on calls incoming to the corresponding station, a source of current adapted'tov be connected to any one of said lines for the purpose of energizing vthe transmitters used in an established connection including said one line, said first station including a line selectingy switch operable to a plurality of positions individually corresponding to said lines to select saiddines for use on calls to the stationscorrespondingfto said lines, a second switch provided at saidrrst station and having a plurality of operating positions, means responsive to operation of said second switch to one of its operating positions for connecting the transmitter and re- "ceiver at said iirst station for usein communicating-over the line corresponding to said iirst station irrespective of the position of said line selecting switch at the time said second switch is operated, meansalso responsive to operation of said second switch to said one position for connecting said source to the line corresponding to said first station, means responsive to operation of said second switch to a second of its operating positions for disconnecting said source from the line corresponding to said rst station and for causing the operation of the signal device located at the station corresponding to the position of said line selecting switch, and means responsive to operation of said second switch to a'third of its operating positions for arresting the operation of said last-mentioned signal .device and for connecting the transmitter and receiver at said rst station for use in communicating over the line corresponding to the position of said line selectingv switch.

5. In a telephone system, a first telephone station, a plurality of additional telephone stations, a signal device at each of said additional stations, each of said stations 4including a transmitter and a receiver, a plurality of lines individually correspondingto said stationsk and each extending between all ofsaid stations, each of saidlines beingV adapted to be used only on calls incoming to the corresponding station, a source of Ycurrent adapted to be connected to any one of said lines for the purpose of energizing the transmitters used inan established connection including said one line, said rst station including a line selecting switch operable to a plurality of positions Aindividually corresponding to said lines tov select said lines for use on calls to the stations corresponding to said lines, a second switch provided at said first station and having a plurality of' operating positions, means responsive to operation oi said second switch to one of its operatingpositions for connecting the transmitter and receiver at said iirst station for use in communicating over the line corresponding to said first station irrespective of the position of said line selectingA h lswitch at the time said second switch is operated,I means also responsive to operation of said second,

switch to said one position for connecting said source to the line corresponding to said first station, `means responsive to operation of vsaid second switch to a second of itsoperating positionsvfor disconnecting said source from the line corresponding to said iirst station and for causing the operation of the signal device located at Switch, and means responsive to operation of said second switchto a fourth of its operating positions lfor, disconnecting the transmitter andreceiver at said first station from all of said lines.

6. In a telephone system, a first telephone station, va plurality of additional telephone stations,

a signal device at each of said additional stations,

each of said stations including a transmitter and a receiver, a plurality oi lines individually corresponding to said stations and each extending between all of said stations, each of said lines being y adapted to be used only on calls incoming to the correspondingv station, a source o current adapted to be connected to any one of said lines for the purpose of energizing the transmitters used in an established connection including said one line,said`fiist station including a line selecting switch operable to a plurality of Apositionsindividually corresponding to said lines to select said'lines for use on calls to the stations correu sponding to said lines, a second switch provided `i at' said first station and having a plurality of operating positions, means responsiveto operation of said second switch to one of its operating positions for connecting the'transmitter and receiver at said first station for use in communicating over the line corresponding to said first station irrespective of the position of said line selecting switch at the time said second switch is operated, means also responsive tooperation of said second switch to said one position for connecting said source to the line corresponding to said first station, means responsive to operation of said second switch to a second of its operating positions for disconnecting said source from the line corresponding to said first station and for caus-I ing'tlie operation of the signal device located at the station corresponding to the position of said line selecting switch, means operated when the call is'answered at said last-mentioned station for arresting the operation of said last-mentioned.

the line corresponding to the position of said line selecting switch, and'means responsive to opera-r tion of said second switch to a third of its operat- .fing positions for connecting the transmitter and receiver at said rst station ior use in communicating over the line correspondingA to the positionl of said line selecting switchl .7. In a'telephone system, station, a plurality of additional telephone 'stations, a signal device at each of said additional stations, each of said stations including' a transmitterand a receiver, a` plurality of .lines individually corresponding to 'said stations and each extending between all of said stations, each of lsaid lines being adapted to be, used only on calls incoming to the corresponding station, a

source of current adapted to be connected to any,w one of saidv lines for the purpose of energizing.

the transmitters used in an established connection including said one line, said iirst station including a line selecting switch operable to a signal device and for connecting said source to.

a rst telephone plurality of positions individually correspondingv` y `to said lines to select said lines for useon calls.` to the stations corresponding to said lines, al

second switch provided at saidrst station and having a plurality of operating positions, means responsive to operation of said second switch to one of its operatingpositions for connecting i the transmitter and receiver at said first station for usein communicating over the line corresponding to said iirst station irrespective of the position of said line selecting switch at the time saidsecond switch isv operated, means also rel sponsive to operation of said second switch to said one position ior'connecting said source to theline corresponding to said first station, means responsive to -operation of said second switch to` a second of 'its loperating positions for disconnecting said source from the line corresponding to said first ystation and for causing the operation of the signal device located at the station corresponding to the position of said line select-y ing switch, means operated when -the` call is answered at said last-mentioned station for arresting the operation'of said last-mentioned signal `device and for connecting said source to the line corresponding to the position of said iine selecting switch, means responsive to operation oi said secondl switch to a third oiits operating positions for connecting the transmitter and receiver at said first station ior use in coinmunicating over the line corresponding to the position of vsaid line selecting switch, and means responsive to operation of said second switch to a fourth of its operating positions vfor disconnecting the transmitter and receiver at said first station from all of said lines.

8. In a telephone system, a rst telephone station including al transmitter and a receiver, a plurality of additional telephone stations, each of said stations including a signal device, a 'plurality of lines individually corresponding to said `stations and each extending between all of said stations, each of said lines being adapted to be used `only on calls incomingto the corresponding Stations, said rst station including a lineselecting switch `operable to a plurality of positions individually corresponding to said lines, a second switch provided at said station and having a plurality lof, `operating positions, means responsive to operation of said second switch to one of its,`

operating vpositions for vconnecting said transmitter and receiver for use in communicating over the line corresponding to said `iirst station ,virrey switch at the time said second switch is operated, means responsive to operation of said second Switch to another of its operating positions for connecting said transmitter and receiver for use in communicating over the line corresponding to the position of said line selecting switch, a circuit for energizing the signal device at said iirst station, and means controlled by said second torv switch for maintaining said circuit preparedwhen said second switch is operated to any of its positions other than said one position.

9. In a telephone system, a first telephone station including a transmitter and a receiver,

a plurality of additional telephone stations, each of said stations including' a signal device, a plurality of lines individually corresponding to said stations and each extending between all of said y, stations, each of said lines being adapted to be used only on calls incoming to the corresponding stations, said first station including a line selecting switch operable to a plurality of positions individually corresponding to said lines, a

,Y second switch provided at said station and hav- 25 ing a plurality of operating positions, a source of current adapted to be connected to any one of said lines for the purpose of energizing the transmitters used in an established connection including said one line, means responsive to operation of said switch to one of its operating positions for connecting the transmitter and receiver at said first station for use in communicating over the line corresponding to said first station irrespective of the position of said line selecting switch at the time said second switch is operated, means also responsive to the operation of said second switch to said one position for connecting said source to the line corresponding to said rst station, means responsive to operation of said second switch to another oi its'operating positions for disconnecting said source from the line corresponding to said rst station and -for connecting said transmitter and receiver for me in communicating over the line corresponding to the position of said line selecting switch, a circuitI for energizing the signal device at said first station, and means controlled by said second switch for maintaining said circuit prepared when said second switch is operated to any of its positions other than said one position.

10. In a telephone system, a first telephone station including a transmitter and a receiver, a plurality of additional telephone stations, each of said stations including a signal device, a plurality of lines individually corresponding to said stations and each extending between all of said stations, each of said lines being adapted to be used only on calls incoming to the corresponding stations, said first station including a line selecting switch operable to a plurality of positions individually corresponding to said lines, a second switch provided at said station and having a plurality of operating positions, means responsive to operation of said second switch to one of its operating positions for connecting said transmitter and receiver for use in communicating over the line corresponding to said rst station irrespective of the position of said line selecting switch at the time said second switch is operated, means responsive to operation of said second switch to asecond oi its positions lfor causing the operation of the. signal device provided at the station corresponding to the position of said line selecting switch, means refsponsive to operation of said second switch to v`stations, each of ars/w44 a third of' its positions for connecting saidrtransmitter and receiverfor usein communicating over the line corresponding to the position of said line selecting switch, a circuit for energizing the signal device at said rst station and means controlled by said second switch for maintaining said circuit prepared when said second switch is operated to any of its positions other than said one position.

11. In a telephone system, a rst telephone station including a transmitter and a receiver, a plurality of additional telephone stations, each of said stations including a signal device, a plurality of lines individually corresponding to said stations and each extending between all of said said lines being adapted to be used only on calls incoming to the corresponding stations, said rst station including a line selecting switch operable to a plurality of positions individually corresponding to said lines, a second switch provided at said station and having a plurality of operating positions, a source of current adapted to be connected to any one of said lines for the purpose of energizing the transmitters being used in an established connection including said one line, means responsive to operation of said switch to one of its operating positions for connecting the transmitter and receiver at said rst station for use in communicating over the line corresponding to said iirst station irrespective of the position of said line selecting switch at the time said second switch is operated, means also responsive tol the operation of said second switch to said one position for connecting said source to the line corresponding to said rst station, means responsive to operation of said second switch toa second of its positions for causing the operation of the signal device provided at the station corresponding to the position of said line selecting switch, means responsive to operation of said second switch to a third of its positions for disconnecting said source from the line corresponding to said first station and for connecting said transmitter and receiver for use ,in com` municating over the line corresponding to the positionof said line selecting switch, a circuit for energizing the signal device at said first station, and means controlled by said second switch for maintaining said circuit prepared when said second switch is operated to any of its positions other than said one position.

12. In a telephone system, a rst telephonestation includingla transmitter and a receiver, a supporting element for said receiver, al plurality of additional telephone stations, a plurality of lines individually corresponding to said stations and each extending between all of said stations, each of said lines being adapted to'be used only on calls incoming to the corresponding station, a switch operative to one position in response to removal of said receiver from its supporting element and manually operable to another position, means responsive to operation` of said switch to its one position for connecting said transmitter and receiver for 'use in communicatingover the line corresponding to said iirst station, and means responsive to operation of said switch to its other position for connecting said transmitter and receiver for use in communicating over a second of said lines.

13. In a telephone system, a iirst telephone station including a transmitter and a receiver,

rality of lines individually corresponding to said stations and each extending between all Lof said stations, each of said lines being adapted to be `used only on calls incoming to the corresponding station, said iirst station including a lin'e selecting switch operable to a plurality of positions individually corresponding to said lines, a second switch operative to one position in response to removal of said receiver from its supporting element and manually operable to another posiv tion, means responsive to operation of said second switch to its one position for connectmg said transmitter 4and receiver for use in communicating over the line corresponding to said rst station irrespective of the position of said line selecting switch, and means responsive to operation of said second switch to its other position for connecting said transmitter and receiver for use in communicating over the line corresponding to the position of said line selecting switch. I

14. In a telephone system, a first telephone stationincluding a transmitter and a receiver, a

Asupporting element for said receiver, a plurality i porting element and manually` loperable to another position, means responsive to operation v ci said switch to its one position for connecting fil",

said transmitter and receiver for use in communicating over the line corresponding to said first station, meansalso responsive to operation of said switch to its one position for connecting said source to the line correspondingto said rst station, and means responsive to operation of said switch to its other position rfor connecting said transmitter and receiver 'for use in communicating'cver a second of said lines.

15. In a telephone system, a lrst telephone station including a transmitter and a receiver, a supporting element for said receiver, a plurality of -additional telephone stations, alsignalfdevice provided at each of said 'additionalstationa a vplurality of linesv individually correspondingto said stations and each extending between all of said stations, each of said lines being adapted to be used only on calls incoming to the corresponding station, saidy first station including a line selecting switch operable to a plurality of positions individually corresponding to said lines, a second switch operative to one position response to removal of said receiver from its supporting element and manually operablev to a 4plurality of other positions, means responsive to operation of said second switch to its one position.

for connecting said transmitter and receiver yfor use in communicating over the line corresponding to said rst station irrespective of the position of said line selecting switch at the time said second switch is operated, means operative in response to operation of said second switch to one of its other positions for causing the operation of the signal devic'e'provided at they station correspondi,

ing to the position of said line selecting switch, and means responsive to operation of said switch to a second of its other positions for connectin said transmitter and receiver for use in communicating over the line corresponding to the position of said line selecting switch.

16, In a telephone system,a rst telephone` station including ay transmitter vand a receiver, a

supporting'element for said receiver, a plurality of additional telephone stations, a plurality 4of lines extending between rsaid stations, a switch operative to one position in response to removal of said receiver from its supporting element and manually operable to another position, means responsive toV operation of said switch to its `one position for connecting said transmitter and receiver foruse in communicating, over one of said lines, and means responsive to operation of said f switch to itsl other position for connecting said transmitter yand receiver for use in communicating over a second of said lines. l

17. In a telephone system, a first telephone station including a transmitter and a receiver, a supadditional telephone stations, a plurality of lines extending between said stations, 4a signal device at each of said stations, a switch operative to one position in response to removal of said receiver from its supporting element and manually opersponsive to operation of said switch toits one position for connecting said transmitter and receiver for use in communicating over one of said` of said other positions for connectingsaid transmitter and receiver for use in communicating over saidsecond line.

18. In a telephone. system, a first telephone station including ati'ansrnitter and a-receiver, a supporting element fori said receiver, a plurality of additionalutelephone stations,l a signal device provided at each of said additional stations,l a plurality of lines individuallycorresponding to said stations and each extending between all of said stations, each of said linesbeing-adaptedto be used only on calls incoming tov the corresponding station, said first station including a line selecting switch operable to a plurality' of `positionsindividually corresponding to said lines, a second switch operative to one' position 4in response to removal of said receiver from its supporting element and manuallyoperableto `a plurality of other positions, means responsive to operation of porting element for said receiver, aplurality of ableto a plurality of other positions, means re-v l said second switch to its one position for cont said line selecting switch at the time said second switch is operated, means operative in response to operation oisaid second switch to one of its other positions for causing the operation of the signal device provided atthe station correspondingto the position of said line selecting switch,

a second of its other positions for connecting said vtransmitter and receiver for usev in communicating over the line corresponding to the position of said line selecting switch, and means responsive to operation of said secondswitch. to a third of s its other positions for "disconnecting said trans- ,K mitter and receiver from all of said lines.`

CLARENCE ERNEST LOMAX.

means responsive to operation of said switch to'k 

